TOSPEL Transient operando spectroscopy of perovskite nanocrystal LEDs

满足对环境影响有限的照明的大幅增长的需求依赖于提供节能照明系统的技术发展。金属卤化物钙钛矿已经成为一类新的半导体，它为我们将电能转化为光的方式带来了革命性的机会。由于其低制造成本、高效率、带隙可调谐性和高色纯度，Permanent Light Emitting Diode（LED）具有成为下一代LED的巨大潜力。尽管钙钛矿型LED具有优势，但不可避免的尺寸分布，形状差异和表面状态导致多种动态过程共存，这些动态过程影响LED的光电特性和操作稳定性。该项目名为“钙钛矿发光二极管的瞬态操作光谱”（TospeL）。将周期性电激发和飞秒光脉冲相结合的新型超快吸收和发射光谱技术将被设计并应用于钙钛矿型OLED。申请人将加入麻省理工学院的Bawendi集团（即将离任的阶段），合成钙钛矿纳米晶体并制造具有理想光学特性的OLED，这些LED将用于使用Bawendi集团新设计的瞬态操作发射技术进行超快动力学研究。对于返回阶段，申请人将加入剑桥大学的Stranks小组，设计和实施瞬态吸收光谱，以研究激子，载流子，陷阱和自旋之间的相互作用以及工作LED中的复合机制。这些结果将使人们对LED的物理特性有一个新的全面的认识，并为LED的进一步发展提供指导。

Meeting the substantially growing demand for lighting with limited environmental impact relies on technological developments delivering an energy-efficient lighting system. Metal-halide perovskites have emerged as a new class of semiconductors that creates opportunities to revolutionize the way we convert electrical energy into light. Perovskite nanocrystal light-emitting diodes (LEDs) have enormous potential to be the next generation of LEDs due to their low fabrication cost, high efficiency, bandgap tunability, and high color purity. Despite the advantages of perovskite nanocrystal LEDs, the inevitable nanocrystal size distribution, shape difference, and surface states lead to the co-existence of multiple dynamic processes that influence the optoelectronic properties and the operational stability of the LEDs. This project is titled "Transient operando spectroscopy of perovskite nanocrystal LEDs" (TospeL). Novel ultrafast absorption and emission spectroscopic techniques combining periodic electrical excitations and femtosecond optical pulses will be designed and applied to perovskite nanocrystal LEDs. The applicant will join the Bawendi Group at MIT (outgoing phase) to synthesize perovskite nanocrystals and fabricate nanocrystal LEDs with desirable optical properties, which will be used for ultrafast dynamics studies using newly designed transient operando emission techniques in the Bawendi Group. For the return phase, the applicant will join the Stranks Group at University of Cambridge to design and implement transient absorption spectroscopy to investigate the interactions between excitons, carriers, traps, and spin as well as the recombination mechanisms in working LEDs. These results will give a new comprehensive understanding of LEDs photophysics and provide guidance for their further development.